Model Answer
0 min readIntroduction
Groundwater constitutes a significant portion of the world’s readily available freshwater resources, serving as a crucial source for drinking, irrigation, and industrial purposes. However, not all groundwater is equally usable. Its suitability for various applications is determined by a complex interplay of chemical, physical, and bacteriological properties. These properties dictate whether the water is safe for consumption, agriculture, or industrial processes. Understanding these parameters and their permissible limits, as defined by organizations like the Bureau of Indian Standards (BIS) and the World Health Organization (WHO), is paramount for effective groundwater resource management and public health protection.
Chemical Properties and Groundwater Usability
Chemical properties significantly impact groundwater quality. These include the concentration of dissolved minerals, organic compounds, and pollutants. Key parameters include:
- Total Dissolved Solids (TDS): High TDS can affect taste and cause scaling in pipes. Permissible limit (BIS): 500 mg/L.
- pH: Indicates acidity or alkalinity. Optimal range for drinking water is 6.5-8.5.
- Hardness: Caused by calcium and magnesium ions. Excessive hardness leads to scaling and reduces soap efficiency.
- Fluoride: Essential in small amounts for dental health, but excess fluoride causes fluorosis (skeletal and dental). Permissible limit (BIS): 1.5 mg/L.
- Nitrate: Primarily from agricultural runoff and sewage. High nitrate levels can cause ‘blue baby syndrome’ (methemoglobinemia) in infants. Permissible limit (BIS): 45 mg/L.
- Iron & Manganese: Cause staining and affect taste.
- Arsenic: A toxic metalloid, often naturally occurring in groundwater in certain geological formations (e.g., Bengal Delta Plain). Long-term exposure leads to various cancers and skin lesions. Permissible limit (BIS): 0.01 mg/L.
Sources of chemical contamination include natural weathering of rocks, agricultural activities (fertilizers, pesticides), industrial discharge, and sewage.
Physical Properties and Groundwater Usability
Physical properties influence the aesthetic qualities and usability of groundwater. Important parameters are:
- Turbidity: Cloudiness caused by suspended particles. High turbidity reduces light penetration and can harbor pathogens.
- Color: Can be caused by dissolved organic matter, iron, or manganese.
- Taste & Odor: Influenced by dissolved gases, organic compounds, and minerals.
- Temperature: Affects solubility of gases and chemical reaction rates.
- Electrical Conductivity: Indicates the amount of dissolved salts; related to TDS.
These properties, while often not directly harmful, can make water unpalatable or require treatment before use. High turbidity, for example, necessitates filtration.
Bacteriological Properties and Groundwater Usability
Bacteriological contamination is a major concern for drinking water quality. The presence of pathogenic microorganisms indicates fecal pollution and poses a significant health risk.
- Coliform Bacteria: Indicator organisms for fecal contamination. Their presence suggests the potential for other harmful pathogens.
- Escherichia coli (E. coli): A specific type of coliform bacteria, strongly indicative of recent fecal contamination.
- Viruses & Protozoa: Can cause various gastrointestinal illnesses.
Sources of bacteriological contamination include sewage leaks, inadequate sanitation, and agricultural runoff. Groundwater is generally filtered by the soil, but in areas with shallow water tables or fractured bedrock, contamination can occur rapidly. Disinfection (chlorination, UV irradiation) is crucial to eliminate pathogens.
| Property | Key Parameters | Impact on Usability | Remedial Measures |
|---|---|---|---|
| Chemical | Nitrate, Arsenic, Fluoride, TDS | Health risks, aesthetic issues, industrial limitations | Reverse Osmosis, Ion Exchange, Defluoridation, Blending |
| Physical | Turbidity, Color, Taste/Odor | Aesthetic issues, reduced disinfection efficiency | Filtration, Aeration, Activated Carbon Adsorption |
| Bacteriological | Coliforms, E. coli, Viruses | Waterborne diseases | Disinfection (Chlorination, UV, Ozone) |
Conclusion
In conclusion, the usability of groundwater is intricately linked to its chemical, physical, and bacteriological properties. Regular monitoring of these parameters against established standards is essential to ensure safe and sustainable water resources. Addressing contamination sources through improved sanitation, agricultural practices, and industrial regulations is crucial. Furthermore, appropriate water treatment technologies must be employed to render groundwater suitable for its intended use, safeguarding public health and supporting economic development. A holistic approach to groundwater management, integrating scientific assessment with policy interventions, is vital for long-term sustainability.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.